☣️ UN 1405 • CLASS 4
UN 1405 — Calcium silicide
Placard: Dangerous When Wet. ERG Guide 138. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
🚒☣️
⚠️ This page is a quick-reference aid. For real incidents: stage upwind, isolate, deny entry, request Hazmat early, and consult the current ERG + SOP/SOG.
Calcium silicide is a highly reactive substance that can produce flammable gases when exposed to water. It is essential to handle this substance with extreme caution.
Hazard overview: Calcium silicide can react violently with water, producing flammable hydrogen and silane gases. It may also ignite spontaneously.
Response guidance: In case of a spill, isolate the area 25-50m in all directions and evacuate the immediate area if water contact occurs or a fire develops. Use dry chemical, dry sand, or soda ash to extinguish the fire.
Advertisement
UN 1405 Quick Details
UN 1405
Product name: Calcium silicide
DOT Class: 4
Placard type: Dangerous When Wet
ERG Guide: 138 (check current ERG)
Initial isolation: ERG 138: isolate 25-50m in all directions; evacuate immediate area if water contact occurs or fire develops
Common Hazards of UN 1405
- Produce flammable gases on contact with water.
- May ignite on contact with water or moist air.
- Some react vigorously or explosively on contact with water.
- May be ignited by heat, sparks or flames.
- May re-ignite after fire is extinguished.
- Some are transported in highly flammable liquids.
- Runoff may create fire or explosion hazard.
- Inhalation or contact with vapors, substance or decomposition products may cause severe injury or
Chemical Identity & Physical Properties
Calcium silicide appears as a gray to black crystalline solid or powder with no distinct odor.
| Also known as | Calcium disilicideSilicide of calciumCalcium silicon alloy |
| CAS Number | 12013-56-8 |
| Appearance | Gray to black crystalline solid or powder with no distinct odor. Hygroscopic material that reacts with moisture. |
| Flash Point | Not applicable (water-reactive solid) |
| Boiling Point | Not applicable (decomposes on contact with water) |
| Vapor Density | Not applicable (solid) |
| Water Reactivity | Reacts violently with water producing flammable hydrogen and silane gases; may spontaneously ignite |
Chemical details are general reference only. Always verify with current SDS, ERG, and SOP/SOG.
Fireground Response Guidance — UN 1405
Extinguishing Media
Dry chemical, dry sand, soda ash; never use water or foam
PPE Requirements
⚠️ Level B minimum; SCBA required; chemical-resistant suit for spill response
Level B minimum personal protective equipment (PPE) is required, including a self-contained breathing apparatus (SCBA) and chemical-resistant suit for spill response.
Isolation & Evacuation
ERG 138: isolate 25-50m in all directions; evacuate immediate area if water contact occurs or fire develops
Always confirm protective actions with the current edition of the Emergency Response Guidebook (ERG Guide 138).
First Actions for a UN 1405 Incident
- Keep unauthorized personnel away.
- Stay upwind, uphill and/or upstream.
- Ventilate closed spaces before entering, but only if properly trained and equipped.
- Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
- Consider initial downwind evacuation for at least 300 meters (1000 feet).
Advertisement
📋 Copy & Share Field Card
UN 1405 — Calcium silicideHAZMAT RADIO NOTE — UN 1405
Product: Calcium silicide
Class 4 / Dangerous When Wet / ERG 138
PPE: Level B minimum; SCBA required; chemical-resistant suit for spill response
ISOLATION: ERG 138: isolate 25-50m in all directions; evacuate immediate area if water contact occurs or fire develops
ACTION: Stage upwind · Isolate · Deny entry · Request HazmatRADIO
Use for: Quick radio or face-to-face size-up. Short, structured, field-ready.
=== IC HAZMAT BRIEFING ===
UN 1405 — Calcium silicide
Class: 4 | Placard: Dangerous When Wet | ERG Guide: 138
Appearance: Gray to black crystalline solid or powder with no distinct odor. Hygroscopic material that reacts with moisture.
Water Reactivity: Reacts violently with water producing flammable hydrogen and silane gases; may spontaneously ignite
Extinguishing: Dry chemical, dry sand, soda ash; never use water or foam
PPE: Level B minimum; SCBA required; chemical-resistant suit for spill response
Isolation: ERG 138: isolate 25-50m in all directions; evacuate immediate area if water contact occurs or fire develops
— Key Hazards —
• Produce flammable gases on contact with water.
• May ignite on contact with water or moist air.
• Some react vigorously or explosively on contact with water.
— First Actions —
• Keep unauthorized personnel away.
• Stay upwind, uphill and/or upstream.
• Ventilate closed spaces before entering, but only if properly trained and equipped.
• Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters
SOURCE: allfirefighter.com/hazmat/un/calcium-silicide-un-1405 | Always use current ERG + SOP/SOGIC BRIEFING
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
UN1405 Calcium silicide Cls4 ERG138 | allfirefighter.com/hazmat/un/calcium-silicide-un-1405SMS / 160 CHAR
Use for: Quick text to command or incoming units. Fits in a single SMS.
⚠️ Quick-reference only. Always use current ERG + SOP/SOG for incident-specific actions.
Page: https://allfirefighter.com/hazmat/un/calcium-silicide-un-1405
Advertisement
Frequently Asked Questions about UN 1405
Yes, UN 1405 can produce flammable gases on contact with water.
Yes, UN 1405 may ignite spontaneously on contact with water.
Avoid water contact when handling UN 1405.
Sources (high level): DOT/PHMSA marking & class concepts + ERG usage principles.
This page does not reproduce ERG guide text—always consult the current ERG for incident-specific protective actions.